Time-resolved pre-treatment portal dosimetry systems, devices, and methods

• US 10,265,546 B2
• Filed: 01/20/2016
• Issued: 04/23/2019
• Est. Priority Date: 11/07/2013
• Status: Active Grant

• Current Assignee: Siemens Healthineers International AG
• Original Assignee: Varian Medical Systems International AG (Siemens AG)
• Inventors: Verhaegen, Frans, Podesta, Mark, Nijsten, Sebastiaan M. J. J. G., Persoon, Lucas C. G. G., Baltes, Christof, Scheib, Stefan G.
• Primary Examiner(s): Nguyen, Kiet T
• Application Number:
  US15/002,205
• Publication Number:
  US 20160136459A1
• Time in Patent Office: 1,189 Days
• Field of Search: 378 65, 378 62, 382132
• CPC Class Codes: A61N 2005/1054 using a portal imaging system
• CPC Class Codes: A61N 5/1031 using a specific method of dose optimization
• CPC Class Codes: A61N 5/1047 with movement of the radiation head during application of radiation, e.g. for intensity modulated arc therapy or IMAT
• CPC Class Codes: A61N 5/1071 for verifying the dose delivered by the treatment plan
• CPC Class Codes: A61N 5/1075 for testing, calibrating, or quality assurance of the radiation treatment apparatus

Abstract

Systems, devices, and methods for pre-treatment verification of radiation dose delivery in arc-based radiation therapy devices using a time-dependent gamma evaluation method.

Claims

1. A dosimetric evaluation method, comprising:

generating a sequence of portal dose images, the portal dose images in the sequence corresponding to measured radiation doses delivered at predetermined time intervals according to a treatment plan,

comparing the generated portal dose images with corresponding predicted portal dose images for corresponding time intervals in the sequence, and determining discrepancies between the generated portal dose images and corresponding predicted portal dose images using a time-dependent gamma evaluation method; and

evaluating radiation dose delivery based on the determined discrepancies,

wherein the evaluating is in real-time, and

wherein the evaluating includes determining a dose delivery error.

2. The method of claim 1, wherein the time intervals comprise control points (CPs) of the radiation treatment plan.

3. The method of claim 1, wherein the comparing comprises comparing dose distributions.

4. A method for verifying quantities of interest of a delivered radiation beam, comprising:

acquiring portal dose images during radiation beam delivery;

resampling the acquired portal dose images into respective time divisions, the time divisions comprising control points (CPs) of a radiation treatment plan, to obtain a sequence of measured portal dose images;

comparing the measured portal dose images in the sequence with corresponding predicted portal dose images and determining discrepancies between the measured portal dose images and corresponding predicted portal dose images using a gamma evaluation method; and

determining dose delivery errors based on the determined discrepancies,

wherein the determining is in real-time.

5. The method of claim 4, wherein the gamma evaluation method is a time-dependent gamma evaluation method.

6. The method of claim 4, wherein the verifying is with a patient in the radiation beam.

7. A system for verifying a quantity of interest of a radiation beam, comprising:

a portal imaging device configured to measure incident radiation dose from predetermined radiation fields and to generate a first series of portal dose images; and

a processing device operably connected to the portal dose imaging device and configured to store the first series of portal dose images in a first data array having spatial locations and time of delivery of the predetermined radiation fields as dimensions, the processing device being further configured to store predicted portal dose images as a second series of portal dose images in a second data array having spatial locations and time of delivery of radiation fields corresponding to the second series of portal dose images as dimensions,

wherein the processing device is further configured to compare points in the first data array with corresponding points in the second data array using a 4D gamma evaluation method, the gamma evaluation method including dose differences, spatial differences, and time differences between corresponding points in the first and second data arrays as parameters,

wherein the quantity of interest includes radiation dose, and

wherein errors in the quantities of interest are determined in real-time based on the comparison.

8. The system of claim 7, wherein the quantities of interest is of a radiation beam in a radiation therapy device.

9. The system of claim 8, wherein the radiation therapy device is a dynamic radiation therapy device.

10. The system of claim 7, wherein the portal imaging device is an electronic portal imaging device (EPID).

11. A system including a radiation therapy device and a computer processing system which executes a sequence of programmed instructions embodied on a computer-readable storage medium to cause the computer processing system to:

initiate radiation beam delivery in the radiation therapy device according to a radiation treatment delivery plan;

acquire portal dose images during the radiation beam delivery;

resample the portal dose images into time divisions to obtain a sequence of measured portal dose images;

compare the measured portal dose images in the sequence with corresponding predicted portal dose images using a time-dependent gamma evaluation method; and

determine radiation dose delivery errors based on the comparison.

12. The system of claim 11, wherein the time-dependent gamma evaluation method includes a 4D evaluation method including time as the fourth dimension.

13. The system of claim 11, wherein the determining includes determining radiation dose.

14. The system of claim 11, wherein the determining is in real-time.

15. The system of claim 11, further including storing the predicted portal dose images as a first data set including positional information and time information of points in the predicted portal dose images as parameters, and storing the measured portal dose images as a second data set including positional information and time information of points in the measured portal dose images as parameters, wherein the positional information includes spatial locations of predicted and measured radiation fields, and the time information includes times of the predicted and measured radiation fields, and wherein the comparing includes comparing the first and second data sets using the time-dependent gamma evaluation method.

16. The system of claim 11, wherein the portal dose images are obtained in real-time with a patient in the radiation beam.